Resistive memory having confined filament formation

ABSTRACT

Resistive memory having confined filament formation is described herein. One or more method embodiments include forming an opening in a stack having a silicon material and an oxide material on the silicon material, and forming an oxide material in the opening adjacent the silicon material, wherein the oxide material formed in the opening confines filament formation in the resistive memory cell to an are enclosed by the oxide material formed in the opening.

PRIORITY INFORMATION

This application is a Continuation of U.S. application Ser. No.14/478,408 filed Sep. 5, 2014, which is a Divisional of U.S. applicationSer. No. 13/465,166 filed May 7, 2012 and issued Oct. 7, 2014 as U.S.Pat. No. 8,853,713, the specifications of which are incorporated hereinby reference.

TECHNICAL FIELD

The present disclosure relates generally to semiconductor memorydevices, methods, and systems, and more particularly, to resistivememory having confined filament formation.

BACKGROUND

Memory devices are typically provided as internal, semiconductor,integrated circuits and/or external removable devices in computers orother electronic devices. There are many different types of memory,including random-access memory (RAM), read only memory (ROM), dynamicrandom access memory (DRAM), synchronous dynamic random access memory(SDRAM), flash memory, and resistive, e.g., resistance variable, memory,among others. Types of resistive memory include programmable conductormemory, resistive random access memory (RRAM), phase change randomaccess memory (PCRAM), magnetoresistive random access memory (MRAM; alsoreferred to as magnetic random access memory), and conductive-bridgingrandom access memory (CBRAM), among others.

Memory devices such as resistive memory devices may be utilized asnon-volatile memory for a wide range of electronic applications in needof high memory densities, high reliability, and low power consumption.Non-volatile memory may be used in, for example, personal computers,portable memory sticks, solid state drives (SSDs), personal digitalassistants (PDAs), digital cameras, cellular telephones, portable musicplayers such as MP3 players, movie players, and other electronicdevices. Data, such as program code, user data, and/or system data, suchas a basic input/output system (BIOS), are typically stored innon-volatile memory devices.

Resistive memory such as RRAM includes resistive memory cells that canstore data based on the resistance state of a storage element, e.g., aresistive memory element having a variable resistance. As such,resistive memory cells can be programmed to store data corresponding toa target data state by varying the resistance level of the resistivememory element. Resistive memory cells can be programmed to a targetdata state, e.g., corresponding to a particular resistance state, byapplying sources of an electrical field or energy, such as positive ornegative electrical pulses, to the cells, e.g., to the resistive memoryelement of the cells, for a particular duration. The electrical pulsescan be, for example, positive or negative voltage or current pulses.

One of a number of data states, e.g., resistance states, can be set fora resistive memory cell. For example, a single level cell (SLC) may beprogrammed to one of two data states, e.g., logic 1 or 0, which candepend on whether the cell is programmed to a resistance above or belowa particular level. As an additional example, various resistive memorycells can be programmed to one of multiple different resistance statescorresponding to multiple data states. Such cells may be referred to asmulti state cells, multi-digit cells, and/or multilevel cells (MLCs),and can represent multiple binary digits of data (e.g., 10, 01, 00, 11,111, 101, 100, 1010, 1111, 0101, 0001, etc.).

Resistive memory cells such as RRAM cells may include conductivefilament formed therein. The conductive filament can serve as aresistive switching element for the cell, e.g., of the resistive memoryelement of the cell.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1E illustrate process steps associated with forming a resistivememory cell in accordance with one or more embodiments of the presentdisclosure.

FIGS. 2A-2C illustrate process steps associated with forming a resistivememory cell in accordance with one or more embodiments of the presentdisclosure.

FIGS. 3A-3C illustrate process steps associated with forming a resistivememory cell in accordance with one or more embodiments of the presentdisclosure.

FIGS. 4A-4C illustrate process steps associated with forming a resistivememory cell in accordance with one or more embodiments of the presentdisclosure.

DETAILED DESCRIPTION

Resistive memory having confined filament formation is described herein.One or more method embodiments include forming an opening in a stackhaving a silicon material and an oxide material on the silicon material,and forming an oxide material in the opening adjacent the siliconmaterial, wherein the oxide material formed in the opening confinesfilament formation in the resistive memory cell to an area enclosed bythe oxide material formed in the opening.

Resistive memory, e.g., resistive memory cells, in accordance with oneor more embodiments of the present disclosure can have a smaller contactarea between the ion source material of the cell and the resistivememory material of the cell. Accordingly, resistive memory, e.g.,resistive memory cells, in accordance with one or more embodiments ofthe present disclosure can have a smaller area in which conductivefilament may form than previous resistive memory. That is, resistivememory in accordance with one or more embodiments of the presentdisclosure can confine filament formation to a smaller area in theresistive memory than previous resistive memory because resistive memoryin accordance with one or more embodiments of the present disclosure canhave a smaller contact area between the ion source material and theresistive memory material than previous resistive memory. Accordingly,resistive memory in accordance with one or more embodiments of thepresent disclosure may have a higher switching uniformity and/or lowervariability between cells than previous resistive memory, which canincrease the performance, consistency, and/or reliability of theresistive memory.

In the following detailed description of the present disclosure,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration how a number of embodimentsof the disclosure may be practiced. These embodiments are described insufficient detail to enable those of ordinary skill in the art topractice a number of embodiments of this disclosure, and it is to beunderstood that other embodiments may be utilized and that process,electrical, or mechanical changes may be made without departing from thescope of the present disclosure.

The figures herein follow a numbering convention in which the firstdigit or digits correspond to the drawing figure number and theremaining digits identify an element or component in the drawing.Similar elements or components between different figures may beidentified by the use of similar digits. For example, 104 may referenceelement “04” in FIGS. 1A-1E, and a similar element may be referenced as204 in FIGS. 2A-2C.

As will be appreciated, elements shown in the various embodiments hereincan be added, exchanged, and/or eliminated so as to provide a number ofadditional embodiments of the present disclosure. In addition, as willbe appreciated, the proportion and the relative scale of the elementsprovided in the figures are intended to illustrate the embodiments ofthe present invention, and should not be taken in a limiting sense.

As used herein, “a number of” something can refer to one or more suchthings. For example, a number of memory cells can refer to one or morememory cells.

FIGS. 1A-1E illustrate process steps associated with forming a resistivememory cell in accordance with one or more embodiments of the presentdisclosure. FIG. 1A illustrates a schematic cross-sectional view of avertical, e.g., film, stack 100 having a resistive memory material 102,a silicon material 104 on resistive memory material 102, and an oxidematerial 106 on silicon material 104.

Resistive memory material 102 can be, for example, a resistive randomaccess memory (RRAM) material such as zirconium dioxide (ZrO₂) orgadolinium oxide (GdO_(x)). Other RRAM materials can include, forexample, colossal magnetoresistive materials such asPr_((1-x))Ca_(x)MnO₃ (PCMO), La_((1-x))CaxMnO₃ (LCMO), andBa_((1-x))Sr_(x)TiO₃. RRAM materials can also include metal oxides, suchas alkaline metal oxides, e.g., Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, BeO, MgO,CaO, SrO, and BaO, refractive metal oxides, e.g., NbO, NbO₂, Nb₂O5,MoO₂, MoO₃, Ta₂O₅, W₂O₃, WO₂, WO₃, ReO₂, ReO₃, and Re₂O₇, and binarymetal oxides, e.g., Cu_(x)O_(y), WO_(x), Nb₂O₅, Al₂O₃, Ta₂O₅, TiO_(x),ZrO_(x), Ni_(x)O, and Fe_(x)O. RRAM materials can also includeGe_(x)Se_(y), and other materials that can support solid phaseelectrolyte behavior. Other RRAM materials can include perovskite oxidessuch as doped or undoped SrTiO₃, SrZrO₃, and BaTiO₃, and polymermaterials such as Bengala Rose, AlQ₃Ag, Cu-TCNQ, DDQ, TAPA, andFluorescine-based polymers, among other types of RRAM materials.Embodiments of the present disclosure are not limited to a particulartype of RRAM material.

Silicon material 104 can be, for example, silicon (Si) or siliconnitride (Si₃N₄), among other types of silicon materials. Oxide material106 can be, for example, an oxide dielectric such as silicon dioxide(SiO₂) or zirconium dioxide (ZrO₂), among other types of oxidematerials. Embodiments of the present disclosure are not limited to aparticular type of silicon material or oxide material.

FIG. 1B illustrates a schematic cross-section view of the structureshown in FIG. 1A after a subsequent processing step. A portion ofvertical stack 100 is removed, e.g., etched and/or patterned, to formopening 108 in vertical stack 100 shown in FIG. 1B. Opening 108 can be,for example, a trench formed in silicon material 104 and oxide material106. In the embodiment illustrated in FIG. 1B, the trench is formed allthe way through oxide material 106 and silicon material 104, and stopson resistive memory material 102. However, in some embodiments, thetrench may extend into resistive memory material 102.

As shown in FIG. 1B, resistive memory material 102, silicon material104, and oxide material 106 form the boundaries of opening 108. Forexample, a portion of the top surface of resistive memory material 102defines the bottom of opening 108, and one or more sides of siliconmaterial 104 and oxide material 106 define the sidewalls of opening 108,as illustrated in FIG. 1B. Although the sidewalls of opening 108 shownin FIG. 1B are parallel, or near parallel, to each other, embodiments ofthe present disclosure are not so limited. For example, opening 108 canhave shapes other than that shown in FIG. 1B.

Opening 108 can have a width 109, e.g., a distance between thesidewalls, of, for example, 30 to 40 nanometers. In some embodiments,the width of opening 108 can be equal to one feature width, e.g.,photolithographic dimension.

Opening 108 can be formed in vertical stack 100 in a manner known in theart. For example, opening 108 can be formed by etching through verticalstack 100, as shown in FIG. 1B. Further, opening 108 can be formed in asingle etch through vertical stack 100, or in a series of etches throughvertical stack 100, e.g., a first etch that removes a portion of oxidematerial 106 and a second, subsequent etch that removes a portion ofsilicon material 104.

FIG. 1C illustrates a schematic cross-section view of the structureshown in FIG. 1B after a subsequent processing step. A metal material110 is selectively formed, e.g., selectively deposited, in opening 108adjacent silicon material 104 and on a portion of resistive memorymaterial 102, as illustrated in FIG. 1C. Metal material 110 can beselectively formed in opening 108 adjacent silicon material 104 and onthe portion of resistive memory material 102 using, for example, aselective atomic layer deposition (ALD) process.

Metal material 110 can be, for example, a copper material. However,embodiments of the present disclosure are not limited to a particulartype of metal material, and can include any type of metal that can beselectively formed in opening 108 adjacent silicon material 104 and onthe portion of resistive memory material 102.

As used herein, selectively forming metal material 110 in opening 108can include forming metal material 110 in opening 108 such that metalmaterial 110 does not form in opening 108 adjacent oxide material 106,e.g., such that metal material 110 is formed exclusively adjacentsilicon material 104 and on a portion of resistive memory material 102,as illustrated in FIG. 1C. That is, metal material 110 adheres tosilicon material 104, but not oxide material 106, such that opening 108is the only location in which metal material 110 is formed, asillustrated in FIG. 1C.

FIG. 1D illustrates a schematic cross-section view of the structureshown in FIG. 1C after a subsequent processing step. Metal material 110is oxidized to form metal oxide, e.g., copper oxide (CuOx), material 112in opening 108. Metal oxide material 112 may be annular shaped and mayalso be adjacent a portion of oxide material 106. That is, metal oxidematerial 112 may cover a portion, e.g., not all, of the bottom ofopening 108, the sides of silicon material 104 that define the sidewallsof opening 108, and a portion, e.g., not all, of the sides of oxidematerial 106 that define the sidewalls of opening 108, as shown in FIG.1D. Further, metal oxide material 112 does not completely fill theportion of opening 108 formed by the bottom of opening 108 and the sidesof silicon material 104 that define the sidewalls of opening 108, asillustrated in FIG. 1D.

Metal oxide material 112 can confine, e.g., restrict, filament formationin the resistive memory cell to the area enclosed by the metal oxidematerial 112. For example, metal oxide material 112 can prevent afilament, e.g., conductive filament, from forming in the cell outside ofthe area enclosed by metal oxide material 112. The area enclosed by themetal oxide material 112 in which filament may form can include, forexample, the unfilled portion of opening 108 formed by the bottom ofopening 108 and the sides of silicon material 104 that define thesidewalls of opening 108.

FIG. 1E illustrates a schematic cross-section view of the structureshown in FIG. 1D after a subsequent processing step. An ion sourcematerial 114 is formed in opening 108 and on oxide material 106. Forexample, ion source material 114 is formed in opening 108 adjacent oxidematerial 106 and metal oxide material 112, and on a portion of resistivememory material 102. Ion source material 114 can be formed in opening108 and on oxide material 106 using, for example, a chemical vapordeposition (CVD) or ALD process.

As shown in FIG. 1E, ion source material 114 completely fills the areaenclosed by metal oxide material 112. Additionally, ion source material114 completely fills the portion of opening 108 formed by the sides ofoxide material 106 that define the sidewalls of opening 108, asillustrated in FIG. 1E.

Ion source material 114 can be, for example, an ion source material forRRAM, such as copper telluride (CuTe) or silver sulfide (Ag₂S). However,embodiments of the present disclosure are not limited to a particulartype of ion source material.

The structure illustrated in FIG. 1E can be a portion of a resistivememory cell, e.g., resistive memory cell 116. For example, resistivememory material 102 can be the storage element of resistive memory cell116. Resistive memory cell 116 can be, for example, an RRAM cell.

The area enclosed by the metal oxide material 112 can have a width 115,e.g., diameter, of, for example, 5 to 15 nanometers. As such, thecontact area between resistive memory material 102 and ion sourcematerial 114 can be smaller than in previous resistive memory cells.Accordingly, the area in resistive memory cell 116 in which filament mayform can be smaller than in previous resistive memory cells. That is,metal oxide material 112 can confine filament formation in the resistivememory cell to a smaller area than in previous resistive memory cellsbecause metal oxide material 112 can create a smaller contact areabetween resistive memory material 102 and ion source material 114 thanin previous resistive memory cells. Accordingly, the resistive memorycell may have a higher switching uniformity and/or lower variabilitybetween other resistive memory cells than previous resistive memorycells, which can increase the performance, consistency, and/orreliability of the resistive memory cell.

FIGS. 2A-2C illustrate process steps associated with forming a resistivememory cell in accordance with one or more embodiments of the presentdisclosure. The structure, e.g., vertical stack 200, illustrated in FIG.2A can be analogous to the structure, e.g., vertical stack 100,illustrated in FIG. 1D, except that resistive memory material 102 hasbeen replaced by an electrode 222. For example, vertical stack 200includes a silicon material 204 analogous to silicon material 104 onelectrode 222, an oxide material 206 analogous to oxide material 106 onsilicon material 204, an opening 208 analogous to opening 108 formed invertical stack 200, and a metal, e.g., copper, oxide material 212analogous to metal, e.g., copper, oxide material 112 formed in opening208.

Electrode 222 can be, for example, a metal such as tungsten or platinum,among other metals. However, embodiments of the present disclosure arenot limited to a particular type of electrode.

FIG. 2B illustrates a schematic cross-section view of the structureshown in FIG. 2A after a subsequent processing step. A resistive memorymaterial 224 is formed, e.g., deposited, in opening 208. For example,resistive memory material 224 is formed in opening 208 adjacent oxidematerial 206 and metal oxide material 212, and on a portion of electrode222.

As shown in FIG. 2B, resistive memory material 224 does not completelyfill the area enclosed by metal oxide material 212. Additionally,resistive memory material 224 does not completely fill the portion ofopening 208 formed by the sides of oxide material 206 that define thesidewalls of opening 208, as illustrated in FIG. 2B.

Resistive memory material 224 can be, for example, ZrO₂ or GdO_(x), orone of the other resistive memory, e.g., RRAM, materials previouslydescribed herein, e.g., in connection with FIG. 1A. However, embodimentsof the present disclosure are not limited to a particular type ofresistive memory material.

FIG. 2C illustrates a schematic cross-section view of the structureshown in FIG. 2B after a subsequent processing step. An ion sourcematerial 226 is formed in opening 208. For example, ion source material226 is formed in opening 208 adjacent, between, and on resistive memorymaterial 224. Ion source material 226 can be formed in opening 208using, for example, a CVD or ALD process.

Ion source material 226 can be, for example, an ion source material forRRAM, such as CuTe or Ag₂S. However, embodiments of the presentdisclosure are not limited to a particular type of ion source material.

The structure illustrated in FIG. 2C can be a portion of a resistivememory cell, e.g., resistive memory cell 228. For example, resistivememory material 224 can be the storage element of resistive memory cell228. Resistive memory cell 228 can be, for example, an RRAM cell.

FIGS. 3A-3C illustrate process steps associated with forming a resistivememory cell in accordance with one or more embodiments of the presentdisclosure. The structure, e.g., vertical stack 300, illustrated in FIG.3A can be analogous to the structure, e.g., vertical stack 100,illustrated in FIG. 1B. For example, vertical stack 300 includes aresistive memory material 302 analogous to resistive memory material102, a silicon material 304 analogous to silicon material 104 onresistive memory material 302, an oxide material 306 analogous to oxidematerial 106 on silicon material 304, and an opening 308 analogous toopening 108 formed in vertical stack 300.

FIG. 3B illustrates a schematic cross-section view of the structureshown in FIG. 3A after a subsequent processing step. Silicon material304 adjacent opening 308 is oxidized to form a silicon dioxide, e.g.,SiO₂, material 332 in opening 308 adjacent silicon material 304 and on aportion of resistive memory material 302, as illustrated in FIG. 3B. Thesilicon dioxide material 332 may be annular shaped and may cover aportion, e.g., not all, of the bottom of opening 308, as shown in FIG.3B. Further, the oxidation of silicon material 304, e.g., the formationof silicon dioxide material 322, may consume a portion of siliconmaterial 304, e.g., the sides of silicon material 304 that define thesidewalls of opening 308, as illustrated in FIG. 3B. Additionally,silicon dioxide material 332 does not completely fill the portion ofopening 308 formed by the bottom of opening 308 and the sides of siliconmaterial 304 that defined the sidewalls of opening 308, as illustratedin FIG. 3B.

Silicon dioxide material 332 can confine filament formation in theresistive memory cell to the area enclosed by silicon dioxide material332, e.g., the unfilled portion of opening 308 formed by the bottom ofopening 308 and the sides of silicon material 304 that defined thesidewalls of opening 308, in a manner analogous to metal oxide material112 previously described herein, e.g., in connection with FIG. 1D.

FIG. 3C illustrates a schematic cross-section view of the structureshown in FIG. 3B after a subsequent processing step. An ion sourcematerial 314 is formed in opening 308 and on oxide material 306, in amanner analogous to ion source material 114 being formed in opening 108and on oxide material 106 as previously described herein, e.g., inconnection with FIG. 1E.

As shown in FIG. 3C, ion source material 314 completely fills the areaenclosed by silicon dioxide material 332. Additionally, ion sourcematerial 314 completely fills the portion of opening 308 formed by thesides of oxide material 306 that define the sidewalls of opening 308, asillustrated in FIG. 3C.

Ion source material 314 can be, for example, an ion source material forRRAM, such as CuTe or Ag₂S. However, embodiments of the presentdisclosure are not limited to a particular type of ion source material.

The structure illustrated in FIG. 3C can be a portion of a resistivememory cell, e.g., resistive memory cell 336. For example, resistivememory material 302 can be the storage element of resistive memory cell336. Resistive memory cell 336 can be, for example, an RRAM cell.

The area enclosed by the silicon dioxide material 332 can have a width333, e.g., diameter, of, for example, 5 to 15 nanometers. As such, thecontact area between resistive memory material 302 and ion sourcematerial 314 can be smaller than in previous resistive memory cells.Accordingly, the area in resistive memory cell 336 in which filament mayform can be smaller than in previous resistive memory cells, in a manneranalogous to resistive memory cell 116 previously described herein,e.g., in connection with FIG. 1E. Accordingly, the resistive memory cellmay have a higher switching uniformity and/or lower variability betweenother resistive memory cells than previous resistive memory cells, whichcan increase the performance, consistency, and/or reliability of thecell.

FIGS. 4A-4C illustrate process steps associated with forming a resistivememory cell in accordance with one or more embodiments of the presentdisclosure. The structure, e.g., vertical stack 400, illustrated in FIG.4A can be analogous to the structure, e.g., vertical stack 300,illustrated in FIG. 3B, except that resistive memory material 302 hasbeen replaced by an electrode 422. For example, vertical stack 400includes a silicon material 404 analogous to silicon material 304 onelectrode 422, an oxide material 406 analogous to oxide material 306 onsilicon material 404, an opening 408 analogous to opening 308 formed invertical stack 400, and a silicon dioxide material 432 analogous tosilicon dioxide material 332 formed in opening 408.

Electrode 422 can be, for example, a metal such as tungsten or platinum,among other metals. However, embodiments of the present disclosure arenot limited to a particular type of electrode.

FIG. 4B illustrates a schematic cross-section view of the structureshown in FIG. 4A after a subsequent processing step. A resistive memorymaterial 424 is formed, e.g., deposited, in opening 408. For example,resistive memory material 424 is formed in opening 408 adjacent oxidematerial 406 and silicon dioxide material 432, and on a portion ofelectrode 422.

As shown in FIG. 4B, resistive memory material 424 does not completelyfill the area enclosed by silicon dioxide material 432. Additionally,resistive memory material 424 does not completely fill the portion ofopening 408 formed by the sides of oxide material 406 that define thesidewalls of opening 408, as illustrated in FIG. 4B.

Resistive memory material 424 can be, for example, ZrO₂ or GdO_(x), orone of the other resistive memory, e.g., RRAM, materials previouslydescribed herein, e.g., in connection with FIG. 1A. However, embodimentsof the present disclosure are not limited to a particular type ofresistive memory material.

FIG. 4C illustrates a schematic cross-section view of the structureshown in FIG. 4B after a subsequent processing step. An ion sourcematerial 426 is formed in opening 408 in a manner analogous to ionsource material 226 being formed in opening 208 previously describedherein, e.g., in connection with FIG. 2C.

Ion source material 426 can be, for example, an ion source material forRRAM, such as CuTe or Ag₂S. However, embodiments of the presentdisclosure are not limited to a particular type of ion source material.

The structure illustrated in FIG. 4C can be a portion of a resistivememory cell, e.g., resistive memory cell 440. For example, resistivememory material 424 can be the storage element of resistive memory cell440. Resistive memory cell 440 can be, for example, an RRAM cell.

CONCLUSION

Resistive memory having confined filament formation is described herein.One or more method embodiments include forming an opening in a stackhaving a silicon material and an oxide material on the silicon material,and forming an oxide material in the opening adjacent the siliconmaterial, wherein the oxide material formed in the opening confinesfilament formation in the resistive memory cell to an area enclosed bythe oxide material formed in the opening.

Although specific embodiments have been illustrated and describedherein, those of ordinary skill in the art will appreciate that anarrangement calculated to achieve the same results can be substitutedfor the specific embodiments shown. This disclosure is intended to coveradaptations or variations of various embodiments of the presentdisclosure. It is to be understood that the above description has beenmade in an illustrative fashion, and not a restrictive one. Combinationof the above embodiments, and other embodiments not specificallydescribed herein will be apparent to those of skill in the art uponreviewing the above description. The scope of the various embodiments ofthe present disclosure includes other applications in which the abovestructures and methods are used. Therefore, the scope of variousembodiments of the present disclosure should be determined withreference to the appended claims, along with the full range ofequivalents to which such claims are entitled.

In the foregoing Detailed Description, various features are groupedtogether in a single embodiment for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the disclosed embodiments of the presentdisclosure have to use more features than are expressly recited in eachclaim. Rather, as the following claims reflect, inventive subject matterlies in less than all features of a single disclosed embodiment. Thus,the following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separateembodiment.

What is claimed is:
 1. A method of processing a resistive memory cell,comprising: forming a stack having a resistive memory material, asilicon material formed on the resistive memory material, an oxidematerial formed on the silicon material; forming an opening in thesilicon material and the oxide material of the stack; selectivelyforming a metal material in a lower portion of the opening on opposingsidewalls of the silicon material and a lower portion of opposingsidewalls of the oxide material such that: the metal material is incontact with an upper surface of the resistive memory material, anentirety of the opposing sidewalls of the silicon material, and thelower portion of opposing sidewalls of the oxide material; the metalmaterial is adjacent a lower portion of the opening; and the metalmaterial does not form adjacent an upper sidewall of the oxide material;and oxidizing all of the metal material; forming an ion source materialin the opening in an area enclosed by the oxidized metal material andcontacting opposing upper sidewalls of the oxide material; wherein theoxidized metal material confines filament formation in the resistivememory cell to an area enclosed by the oxidized metal material.
 2. Themethod of claim 1, wherein the method includes forming the ion sourcematerial in the opening such that the ion source material completelyfills the area enclosed by the oxidized metal material.
 3. The method ofclaim 1, wherein the area enclosed by the oxidized metal material has awidth of 5 to 15 nanometers.
 4. A method of processing a resistivememory cell, comprising: forming a stack having a resistive memorymaterial, a silicon material on the resistive memory material, and afirst oxide material on the silicon material; forming an opening in thesilicon material and the first oxide material of the stack; forming asecond oxide material in a lower portion of the opening on opposingsidewalls of the silicon material and on a lower portion of opposingsidewalls of the first oxide material by: selectively forming a metalmaterial in the lower portion of the opening on opposing sidewalls ofthe silicon material and on the lower portion of opposing sidewalls ofthe first oxide material such that the metal material is in contact withan upper surface the resistive memory material, an entirety of theopposing sidewalls of the silicon material, and the lower portion of theopposing sidewalls of the first oxide material; and oxidizing all of themetal material; and forming an ion source material in the openingcontacting opposing sidewalls of the oxide material and opposingsidewalls of the second oxide material, wherein the ion source materialis copper telluride or silver sulfide.
 5. The method of claim 4, whereinthe second oxide material formed in the opening confines filamentformation in the resistive memory cell to an area enclosed by the secondoxide material.
 6. The method of claim 4, wherein: the stack includes anelectrode on which the resistive memory material is formed.
 7. Aresistive memory cell, comprising: a vertical stack having: a resistivememory material; a silicon material on and directly contacting theresistive memory material; an oxide material on the silicon material;and an oxidized metal material, wherein: the oxidized material is formedbetween opposing sidewalls of the silicon material and in contact withan upper surface of the resistive memory material; and the oxidizedmetal material is formed between lower portions of opposing sidewalls ofthe oxide material; further comprising an ion source material formed inan area enclosed by the oxidized metal material and contacting opposingupper sidewalls of the oxide material.
 8. The resistive memory cell ofclaim 7, wherein the oxidized metal material is formed on a wall of thesilicon material.
 9. The resistive memory cell of claim 8, wherein theion source material is on the resistive memory material and formed on awall of the oxidized metal material.
 10. The resistive memory cell ofclaim 8, wherein the area enclosed by the oxidized metal material has awidth of 5 to 15 nanometers.
 11. The resistive memory cell of claim 8,wherein the oxidized metal material is a copper oxide material.
 12. Theresistive memory cell of claim 7, wherein the silicon material is asilicon nitride material.